A current I flows along the length of an infinitely long, straight, thin walled pipe. Then

the magnetic field at all points inside the pipe is the same, but not zero
the magnetic field is zero only on the axis of the pipe
the magnetic field is different at different points inside the pipe
the magnetic field at any point inside the pipe is zero

Correct answer: the magnetic field at any point inside the pipe is zero

Solution

According to Ampère's law and the properties of magnetic fields generated by current-carrying conductors, the magnetic field inside a hollow conductor is zero due to the symmetry of the current distribution, which results in the cancellation of the magnetic field lines.

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